This application relates to printer apparatus and methods of printing, and more particularly to such apparatus and methods wherein images are printed on a continuously moving receiver member and after printing are severed into discrete sheets.
In the prior art as exemplified by U.S. Pat. No. 5,440,328, there is described a thermal printing apparatus wherein a receiver member is formed as a roll of paper or coated paper and continuously fed through a series of color print stations wherein different color images, for example color separation images, are separately superimposed on an image area of the receiver member as the receiver member is moved from color station to color station. Thereafter, the receiver member with plural color images formed thereon in superposed registered relationship is delivered to a cutting device for separating the now imaged receiver member into discrete sheets. The problem with such apparatus is that, while one portion of the receiver member is receiving images and is in motion from one color print station to another color print station, another portion of the receiver member needs to be cut preferably while the receiver member is stationary.
In U.S. Pat. No. 1,745,442, there is disclosed a clamping device for a web cutting machine wherein a rotary cutter is provided for cutting the web. In order to cut the web a clamping device is provided which provides gripping members that extend for the width of the machine and are adapted to be brought in clamping relationship with the web by means of a cam drive. The cam drive is operated in conjunction with a rotating knife mechanism so that the clamping occurs at a proper timed relationship with respect to operation of the knife itself. In the device described in this patent a cam follower is associated with a swinging plate that is spring biased out of the path of the web. As a cutting action occurs, the cam urges the cam follower to move the swinging plate against the spring bias. The plate is supported so as to be pivoted about an axis that extends generally perpendicular to the direction of advancement of the web. A problem with the apparatus described in this patent is that the subject matter thereof is not related to printing and additionally the pivot axis of the clamping device needs to be relatively distant from the cutting device in order to be out of the path of the web in order to overcome sufficient moment force of the spring.
It is, therefore, an object of the invention to provide in an improved printing apparatus and method for cutting a moving receiver member as it is being printed.
The above objects are met in a printing apparatus having a cutter to sever the receiver member as printing is being made on the receiver member. In accordance with the printing apparatus of the invention a clamping device holds the receiver member as it is being cut by the cutter. In a first aspect of the invention, there is provided a printing apparatus comprising a plurality of printing stations arranged along a path of movement of a receiver sheet moving in a process direction and the printing stations being adapted to record images upon the receiver sheet; and a cutting mechanism having a cutting blade or blades positioned to cut the receiver sheet along a transverse direction to separate a previously printed image on the receiver sheet from a portion of the receiver sheet being currently printed, the cutting mechanism including a clamping member located proximate the cutting blade or blades for stopping movement of the receiver sheet downstream of the clamping mechanism to provide for a substantially square cut relative to the process direction of the receiver sheet.
In a preferred embodiment, a cam member rotates with operation of a rotary cutter. A lever arm includes a cam follower member that engages the cam member, the lever arm being pivotable about an axis that extends generally in the direction of movement of the receiver member immediately upstream of the clamping device. The lever arm engages a clamping member or a secondary lever which in turn engages the clamping member to control movement of the clamping member into engagement with the receiver member to hold the receiver member from movement while it is being cut by the rotary cutter.
In accordance with a second aspect of the invention, there is provided a method for cutting a receiver member in a printing apparatus while printing is being made on the receiver member. The method comprises operating a cutter to sever the receiver member and holding the receiver member as it is being cut by the cutter using a clamping device.
In a preferred embodiment of the method, a cam member is rotated with operation of a rotary cutter. A lever arm that includes a cam follower member engages the cam member. The lever arm pivots about an axis that extends generally in the direction of movement of the receiver member immediately upstream of the clamping device. The lever arm engages a clamping member or a secondary lever which in turn engages the clamping member control movement of the clamping member into engagement with the receiver member to hold the receiver member from movement while it is being cut by the rotary cutter.